U.S. Pat. No. 4,572,611 (Bellman et al.) discloses an apparatus embodying an optical element adapted to focus an image on a receiving surface. That device is a glass body having an integral lens array on at least one surface of the body. In a preferred form, the glass body has lens arrays formed on opposite surfaces, and composed of individual, opposed lens pairs joined by transparent channels. These channels are surrounded by photonucleated, opacified glass.
A lens array may be formed by selective photonucleation of the glass body. This also provides a degree of optical isolation of the transparent channels to prevent light transfer between channels. Such transfer is commonly referred to as "crosstalk".